Repeatability of the six-minute walk test and relation to physical function in survivors of a critical illness

Jennifer A Alison, Patricia Kenny, Madeleine T King, Sharon McKinley, Leanne M Aitken, Gavin D Leslie, Doug Elliott
Physical Therapy 2012, 92 (12): 1556-63

BACKGROUND: The Six-Minute Walk Test (6MWT) is widely used as an outcome measure in exercise rehabilitation. However, the repeatability of the 6MWT performed at home in survivors of a critical illness has not been evaluated.

OBJECTIVE: The purpose of this study was to evaluate, in survivors of a critical illness: (1) the repeatability of the 6MWT performed at home, (2) the effect on estimates of change in functional exercise capacity if only one 6MWT was performed at follow-up assessments, and (3) the relationship between the physical functioning (PF) score of the 36-Item Short-Form Health Survey questionnaire (SF-36) and the 6MWT.

DESIGN: Repeated measures of the 6MWT and SF-36 were obtained.

METHODS: Eligible participants had an intensive care unit (ICU) length of stay of ≥48 hours and were mechanically ventilated for ≥24 hours. Two 6MWTs and the SF-36 were conducted in participants' homes at weeks 1, 8, and 26 after hospital discharge.

RESULTS: One hundred seventy-three participants completed the study. The participants had a mean age of 57 years (SD=16), a mean Acute Physiology and Chronic Health Evaluation II (APACHE II) score on admission of 19 (SD=10), a mean ICU length of stay of 9 days (SD=8), and a mean mechanical ventilation time of 140 hours (SD=137). Of the 173 participants, 110 performed two 6MWTs at weeks 1, 8, and 26. There were significant mean increases in 6-minute walk distance in the second test of 15 m (P<.0001) at week 1, 13 m (P<.0001) at week 8, and 9 m (P=.04) at week 26. If only one 6MWT was performed at weeks 8 and 26, the estimate of change in 6-minute walk distance from week 1 was 19 m less (P<.001) at both weeks 8 and 26. There was a moderate to strong correlation between SF-36 PF score and 6-minute walk distance at each assessment (week 1: r=.62, P<.001; week 8: r=.55, P<.001; and week 26: r=.47, P<.001).

LIMITATIONS: Some study participants were unable to perform a second 6MWT, and these participants may have differed in important aspects of function compared with those individuals who completed two 6MWTs.

CONCLUSIONS: In survivors of a critical illness, the 6MWT in the home environment should be performed twice at each assessment to give an accurate reflection of change in exercise capacity over time. The SF-36 PF score was a strong indicator of 6-minute walk distance in early recovery from a critical illness.

Full Text Links

Find Full Text Links for this Article


You are not logged in. Sign Up or Log In to join the discussion.

Related Papers

Remove bar
Read by QxMD icon Read

Save your favorite articles in one place with a free QxMD account.


Search Tips

Use Boolean operators: AND/OR

diabetic AND foot
diabetes OR diabetic

Exclude a word using the 'minus' sign

Virchow -triad

Use Parentheses

water AND (cup OR glass)

Add an asterisk (*) at end of a word to include word stems

Neuro* will search for Neurology, Neuroscientist, Neurological, and so on

Use quotes to search for an exact phrase

"primary prevention of cancer"
(heart or cardiac or cardio*) AND arrest -"American Heart Association"